Planning is most important when making selections for your new luxury home if you want to stay on budget.
When buying a new home most builders will give you a base price which includes standard selections. Some builders have generous selections, like granite counter tops, while others are set up to keep the price low. You make your selections and if they are more than standard, then that amount is added to your price. Needless to say if you upgrade everything then your house will be over budget. This is where I have seen some problems. Most people start making decisions on what the builder needs first and have a tendency to upgrade on a lot of the early decisions whether these areas are important to them or not. I call them" the might as wells" because that is what people say early on in the project. What happens is when people get to a selection they really want to upgrade, they are already over budget and have to decide to go farther over budget or do without something they really want. This is how a home gets to be 20% over budget.